The document discusses testing HTTP request handlers in Go. It provides examples of testing an HTTP handler function using httptest, testing code that makes outgoing HTTP requests using a mocking library called gock, and injecting dependencies like the system clock for consistent test results. The examples demonstrate best practices for testing HTTP request handling in Go like using interfaces and dependency injection.

1. Golang.tokyo
2018/08/21 (Tue)
( @duck8823 )

2. •
• @duck8823
•
• /
•
• Kotlin
• Golang

3. •
• @duck8823
•
•
•
• Kotlin
• Golang

4. •
• @duck8823
•
•
•
• Kotlin
• Golang

5. CI
• duck8823/duci
• Golang
• Docker

6. CI
• duck8823/duci
• Golang
• Docker

7. CI
• duck8823/duci
• Golang
• Docker

8. Webhooks
(HTTP)
Commit Status
(HTTP)

9. Webhooks
(HTTP)
Commit Status
(HTTP)

10. Webhooks
(HTTP)
Commit Status
(HTTP)

11. ( )
• Incoming HTTP Requests
• Git Docker ( )
•
•
• Outgoing HTTP Requests

13. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

14. Incoming HTTP Requests
func HandlerFunc(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
body, _ := ioutil.ReadAll(r.Body)
w.Write([]byte(fmt.Sprintf("Hello %s.", body)))
}
• HandlerFunc
, . "

15. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}

16. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}
http.ResponseWriter
(*httptest.ResponseRecorder)
*http.Request

17. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}

18. HandlerFunc
func Test_HandlerFunc(t *testing.T) {
// given
req := httptest.NewRequest("HELLO", "/", strings.NewReader("world"))
rec := httptest.NewRecorder()
// when
HandlerFunc(rec, req)
// then
if rec.Code != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, rec.Code)
}
if !reflect.DeepEqual(rec.Body.Bytes(), []byte("Hello world.")) {
t.Errorf("wont %+v, but got %+v","Hello world.", string(rec.Body.Bytes()))
}
}
*httptest.ResponseRecorder

19. chi HandlerFunc
• URL ("/{param}") HandlerFunc
go-chi/chi
// "/{param}"
func ChiHandlerFunc(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
param := chi.URLParam(r.Context(), "param")
w.Write([]byte(fmt.Sprintf("Hello %s.", param)))
}

20. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}

21. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}
context.Context

22. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}
*http.Request
context.Context

23. chi HandlerFunc
func TestChiHandlerFunc(t *testing.T) {
// given
ctx := chi.NewContext()
ctx.Params.Add("param", "world")
req := httptest.NewRequest("HELLO", "/", nil).WithContext(ctx)
rec := httptest.NewRecorder()
// when
ChiHandlerFunc(rec, req)
// then
// ...check rec
}

24. Incoming HTTP Requests
• httptest
• URL

25. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

26. Git Docker (3rd )
•
src-d/go-git moby/moby
•
•

27. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

28. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

29. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

30. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

31. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
}
• ( docker run )

32. type docker struct {
moby *client.Client
}
func (d *docker) Run(image string, cmd ...string) {
ctx := context.Background()
_, err := d.moby.ImagePull(ctx, image, types.ImagePullOptions{})
con, _ := d.moby.ContainerCreate(ctx, &container.Config{
Image: image,
Cmd: cmd
}, nil, nil, "")
err := d.moby.ContainerStart(ctx, con.ID, types.ContainerStartOptions{})
} .
•

33. Mock
• *client.Client
type Moby interface {
ImagePull(...) (...)
ContainerCreate(...) (container.ContainerCreateCreatedBody, error)
ContainerStart(...) error
}
type docker struct {
moby Moby
}

34. Mock
• google/mock/gomock
func TestDocker_Run(t *testing.T) {
ctrl := gomock.NewController(t)
mockMoby := NewMockMoby(ctrl)
mockMoby.EXPECT().
ImagePull(gomock.Any(), gomock.Any(), gomock.Any()).
AnyTimes().
Return(nil, errors.New("error image pull"))
docker := &docker{moby: mockMoby}
docker.Run("centos", "echo", "hello world")
}

35. Git Docker (3rd )
•
• gomock
•
( mock )

36. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

37. package logger
var Writer io.Writer = os.Stdout
func Debug(message string) {
fmt.Fprintf(Writer, "[DEBUG] %sn", message)
}
•
• ( os.Stdout ) io.Writer (*os.File )

38. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

39. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}
) (
).(
1
( ( 2

40. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

41. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

42. func TestDebug(t *testing.T) {
// given
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "[DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
writer.Close()
actual, _ := ioutil.ReadAll(reader)
if string(actual) != expected {
t.Errorf("wont %s, but got %s", expected, actual)
}
}

43. • io.Writer
io.Pipe

44. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

45. •
func Debug(message string) {
now := time.Now().Format("2006-01-02 15:04:05")
fmt.Fprintf(Writer, "%s [DEBUG] %sn", now, message)
}

46. time.Now()
•
func Debug(message string) {
now := clock.Now().Format("2006-01-02 15:04:05")
fmt.Fprintf(Writer, "%s [DEBUG] %sn", now, message)
}
package clock
import "time"
var Now = func () time.Time {
return time.Now()
}

47. func TestDebug(t *testing.T) {
// given
jst, _ := time.LoadLocation("Asia/Tokyo")
clock.Now = func() time.Time {
return time.Date(1987, time.March, 27, 09, 34, 00, 00, jst)
}
// and
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "1987-03-27 09:34:00 [DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
// ...
}

48. func TestDebug(t *testing.T) {
// given
jst, _ := time.LoadLocation("Asia/Tokyo")
clock.Now = func() time.Time {
return time.Date(1987, time.March, 27, 09, 34, 00, 00, jst)
}
// and
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "1987-03-27 09:34:00 [DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
// ...
}
.

49. func TestDebug(t *testing.T) {
// given
jst, _ := time.LoadLocation("Asia/Tokyo")
clock.Now = func() time.Time {
return time.Date(1987, time.March, 27, 09, 34, 00, 00, jst)
}
// and
reader, writer, _ := os.Pipe()
logger.Writer = writer
// and
expected := "1987-03-27 09:34:00 [DEBUG] Hello World.n"
// when
logger.Debug("Hello World.")
// then
// ...
}

50. • ( )
• time.Now

51. • Incoming HTTP Requests
• Git Docker ( ) )
• (
•
• Outgoing HTTP Requests

52. Outgoing HTTP Requests
• EO
• IL P
• H / D G RA

53. Outgoing HTTP Requests
• 2 ) ) / ( (
func TestRequest(t *testing.T) {
defer gock.Off()
gock.New("http://example.com").
Post("/").
Reply(http.StatusOK)
resp, _ := http.Post("http://example.com/", "application/json", nil)
if resp.StatusCode != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, resp.StatusCode)
}
}

54. Outgoing HTTP Requests
• 2 ) ) / ( (
func TestRequest(t *testing.T) {
defer gock.Off()
gock.New("http://example.com").
Post("/").
Reply(http.StatusOK)
resp, _ := http.Post("http://example.com/", "application/json", nil)
if resp.StatusCode != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, resp.StatusCode)
}
}

55. Outgoing HTTP Requests
• 2 ) ) / ( (
func TestRequest(t *testing.T) {
defer gock.Off()
gock.New("http://example.com").
Post("/").
Reply(http.StatusOK)
resp, _ := http.Post("http://example.com/", "application/json", nil)
if resp.StatusCode != http.StatusOK {
t.Errorf("wont %+v, but got %+v", http.StatusOK, resp.StatusCode)
}
}

56. Outgoing HTTP Requests
•
•

57. Webhooks
(HTTP)
Commit Status
(HTTP)

58. Webhooks
(HTTP)
Commit Status
(HTTP)

59. Webhooks
(HTTP)
Commit Status
(HTTP)

60. Webhooks
(HTTP)
Commit Status
(HTTP)

61. Webhooks
(HTTP)
Commit Status
(HTTP)
)& )
.
& &(

62. Webhooks
(HTTP)
Commit Status
(HTTP)

63. • oc
• H
• ) ( k
• P T
• p
• he ) (M